SPRINGFIELD — Nine convicted defendants in Hampden County drug cases may go free in the wake of alleged tampering by a chemist at an Amherst crime lab, a judge ruled Friday.

Hampden Superior Court Judge Richard Carey set bail ranging from $1,000 to $10,000 for the men pending motions for new trials.

Carey reviewed cases involving 10 men, all of whom allegedly had evidence in their cases analyzed by lab technician Sonia Farak of Northampton.

The judge stayed the sentence of nine defendants, but denied a stay for the 10th because his lawyer did not agree to a motion and hearing schedule set by the court.

It was unclear Friday what implications Carey’s ruling might have for criminal cases in Hampshire and Franklin counties. A representative of the Northwestern district attorney’s office, which prosecutes cases in the two counties and Athol, could not be reached for comment.

Chemist charged

In January, Farak, 35, pleaded not guilty in Eastern Hampshire District Court in Belchertown to two counts of tampering with evidence and to cocaine and heroin possession charges. Authorities say the drugs involved were evidence samples from the lab.

Farak was released on $5,000 bail in January and remains under a curfew. Her next court date is April 12.

Carey issued his decisions Friday morning after hearing motions Tuesday from lawyers for the men involved. Each of the men must now file a motion for a new trial in order to keep his sentence stayed, according to the judge’s decisions.

All but one of the men are serving sentences at the Cedar Junction Correctional Institution in Walpole. The remaining defendant was sentence to a two-year sentence in the Hampden County House of Correction.

The crimes the men were convicted of include possession of cocaine with intent to distribute and trafficking.

Seven of the men pleaded guilty to the drug charges they were facing, according to Carey’s decisions. He wrote that suspect test results from the crime lab may have influenced the cases’ outcomes.

He said that a judge may find “the drug certificates allegedly tampered with by Farak were material to the defendant’s decision to enter a guilty plea on the drug charges.”

According to the decisions, new evidence that may come out of the investigation into the alleged lab tampering should be considered by a jury if the two cases that went to trial are tried again.

“The question is not whether the jury’s verdict would have been different, Carey wrote, “but rather whether the new evidence would probably have been a real factor in the jury’s deliberations.”

The dates of the cases range from January 2006 to January 2012, according to court records.

Information about the cases was not immediately available from the Hampden district attorney’s office.